1. Field of the Invention
The present invention relates to the field of a lock for locking a knife blade in an open position, and more particularly to a safety for keeping such a blade lock in a locking position.
2. Description of Related Art
One form of conventional pocket knives are built with a handle and one or more folding blades. The blades in such knives are closed simply by pressing on the back of the blade and rotating the blade to a closed position in the knife handle. Such knives are known for their ability to close when being used if a pressure is inadvertently applied to the back of the blade.
In order to prevent this from happening, and thereby to allow use of both edges of the blade, locks were developed for locking a blade in an open position. This is commonly provided by a lock element that is spring biased to snap into position adjacent to the hinged end of the blade when the blade is opened. A projecting portion of the lock element or other release mechanism is manipulated to move the lock element away from the blade swing path so that the blade can be closed.
Folding knives having such locking blades have become common. However, because the lock feature is defeated by manipulation of an element on the knife handle, it is not unusual for the lock to be defeated inadvertently during use of the knife. If the person using the knife is unaware that the blade is unlocked, it can close unintentionally when a backward force is applied to the knife blade in what is intended to be a safe procedure.
The use of knives with locking blades has therefore not been met with universal acceptance because of the possibility of inadvertently defeating the locking feature during use.